The invention relates to a magnetic tape backing leaf spring particularly for magnetic tape cassettes.
As is known, a cassette magnetic tape is held close against the gap of a magnetic recording/playing head by a backing leaf spring arranged to engage with the tape back side.
Prior leaf springs are defined by an elastically flexible, generally metal reed which carries a contact element in direct engagement relationship with the tape. The contact element is everywhere in the form of a felt pad.
A disadvantage of prior leaf springs relates to the difficulty of securing the felt pad firmly on the elastic reed. To prevent entrainment by the running tape, some special measures are to be taken, such as disclosed in U.S. Pat. No. 4,573,095 to this same Applicant.
Also recognized is that felt pads tend to deform and stiffen after a while into a permanent shape which may not conform and accurately with a magnetic head for which they have been intended. Further, felt pads are affected by ambient conditions of humidity and temperature, and the frictional force applied to the tape will vary significantly contingent on such conditions.
Another problem, and one of growing weight with the application of magnetic tape cassettes to electronic and other delicate apparatus, is that lint or particles may detach from the felt pads and contaminate apparatus components.
In general, moreover, prior leaf spring assemblies involve significant manufacturing cost and time due to their being made from parts to be formed separately and then assembled together. Also, such leaf spring assemblies have a large volume when stored in coils of leaf spring strings or bands. In fact, the felt pads hold the overlaid leaf spring strings in such coils raised into bulky coil formations of relatively few units. Considering that such coils are to be fed into automated cassette-making equipment, it becomes necessary to arrange for coil changes at frequent intervals, which brings about reiterated shutdowns and increased manufacturing costs.